Embodiments of the present application generally relate to an array substrate, a manufacturing method thereof and a display device.
Recently, the liquid crystal display technology has been improved continuously. A thin film transistor liquid crystal display (TFT-LCD) has predominated in the display field because of various advantages of excellent image quality, low energy consumption, eco-friendliness and the like.
There has always been a demand in increasing the size of a liquid crystal display. With increasing of the size of the liquid crystal display, it is required for frequency of a driving circuit thereof to be increased and in turn, mobility of an amorphous silicon transistor is also required to increase. However, mobility of a current amorphous silicon transistor is generally about 0.5 cm2/V·S, and in the case of the size of the liquid crystal display larger than 80 inches and driving frequency of 120 Hz, mobility of 1 cm2/V·S or more is required, and thus, it is impossible for the current amorphous silicon transistor to meet the requirement of the mobility.
A thin film transistor (TFT) substrate comprising an active layer made of a metal oxide (such as, an IGZO and the like) may better meet requirements of a large size liquid crystal display and an active organic light emitting display because of advantages of high mobility, good homogeneity and the like of the metal oxide, thus attracting much attentions and becoming a research focus in recent years.
Conventionally, a structure of the TFT substrate comprising the active layer made of a metal oxide (such as, IGZO and the like) comprises: a gate electrode layer, a gate insulating layer, an active layer and a source/drain electrode layer (i.e., the source electrode and the drain electrode) sequentially positioned on a glass substrate. Such structure is generally formed by a wet etching process. An etchant used in the wet etching process is typically H2SO4, H3PO4 or H2O2. In such acid etchant environment, the metal oxide itself is easily to be etched, or over-etched. Therefore, a barrier layer provided above the active layer is required to be additionally added in the current TFT substrate, to prevent the metal oxide active layer from being etched and thus being destroyed in the case of using a wet etching process to form the source/drain electrode, thereby further improving performance of the TFT substrate. However, an additional single lithography process is required to form such added barrier layer, which may complicate the manufacturing process of the TFT substrate and thus increasing the production cost of the TFT substrate.